Polishing file



Feb. 3, 1959 J. B. wHlTLocK POLISHING FILE Filed May 22, 1957 UnitedStates j This invention relates to hand files and more particularly toan improved hand polishing tile featuring means for clamping readilyreplaceable strips of abrasive material in `place together with'meansfor tensioning such strips as found most suitable for'the work at hand.

There has been proposed heretofore hand files having means by whichreplaceable strips of abrasive material may be clamped to a suitableholder. However, devices of this type as heretofore provided haveserious shortcomings and disadvantages'obviated by this invention. Forexample, the means provided in prior files for securing the oppositeends of the abrasive strips to the holder and for thereafter tensioningthe strips are complex in construction, difficult for the novice to useand the stripe clamping arrangements are unreliable.

The construction provided by the present invention sat. isfactorilyovercomes the-foregoing and other disadvantages of prior files in anunusually satisfactory manner. The elongated main body of the holder isprovided with a simple self-gripping clamp at one end which acts toclamp the adjacent ends of the two strips to the holder. The combinedstrip clamp and the strip tensioning means provided at the rear end ofthe ho-lder co-mprises a single operating handle serving normally as thehandle for the holder and operating by rotation in opposite directionsabout its own axis to release or to tension the two stripssimultaneously depending on the direction in which the wat handle isrotated. Featured is a spring which automatically increases the grippingaction on the strips as the tension is increased. Additionally, thesingle clamping member at the remote end of the holder actsautomatically to increase its gripping action as the tension isincreased on the abrasive strips.

Accordingly, it is a primary object of this invention to provide animproved polishing le having simple means for replaceably clamping oneor more strips of abrasive material therein.

Another object of the invention is the provision of a hand heldpolishing file having a simple easily operated clamp at its end fordetachably clamping one or more strips of replaceable abrasive materialto the holder, one of the clamps being effective to tension the stripsof abrasive material.

Another object of the invention is the provision of a polishing tilewhich can be assembled from simple, inexpensive and easily manufacturedcomponents without need for jigs, dies and other special manufacturing`facilities.

These and other more specific objects will appear upon y Figure 2 is anenlarged central longitudinal se'cqlal l view taken on line 2 2 ofFigure 1;

the file.

rmagtenteci Feb. E, $59

ICC

Referring to Figures 1-3 there is shown a polishing le j vdesignatedgenerally 10 having a main body 11 with flat opposite sides of asuitable width depending upon the use to which the file is to be put.This body may be formed of wood, plastic or of lightweight metal. Theclamping facilityl prov1ded at the forward end preferably comprises aslot extending crosswise of the main body and having the configurationbest shown in Figure 1 and including a narrow portion 12 opening into awide based portion 13 the oppo-site sidewalls 14, 14 of which convergetoward the relatively narrow mouth 15. Seated within narrow portion 12is a strip of soft rubber or other elastic material 16 the forward endof which terminates close to the plane of mouth 15 and having sufficientclearance from sides 14 as to permit the insertion of the ends ofabrasive strips therepast. A suitable keeper 17 conveniently provided bya round wooden dowel pin 17 has a diameter appreciably greater' than thewidth of mouth 15 and resiliently urged toward this mouth by elasticstrip 16. As is shown in Figure 2, keeper 17 has a length correspondingto the lWidth of main body 11 so that its ends do not project beyond theedges of the main body yet are conveniently accessible to the tips oftheusers thumb and indexiinger so thaty pressure can be applied to theopposite ends when compressing strip 16 sufficiently to permit thewithdrawal and insertion of the'ends of the abrasive strips. l v

TheV` releasable clamping means provided at the rear end of-main body 11comprises a handle grip 20 having a central bore" 21 loosely receiving along bolt 22 the threaded forward end of which is threaded into a bore24 prevent unthreading of these components.' lt will be` understood thatbolt 22 likewise has a tight iit with threaded bore 24 and is turnedinto this bore until the forward lend of sleeve 25 bears lightly againstend wall 26 of the main body, a washer or suitable low frictiondevicebe'ingl inserted ifdesired between surface 26 and the endofthimble 25. Accordingly, it will be understood that hand grip 26 andsleeve 25 are free to rotate about the stationary` mandrel or supportprovided by the body of bolt 22. f

The clamping device forv the adjacent ends of the abrasive stripsvcomprises a pair of at jaws or plates 28 and 29 having their facingsurfaces lying close together and forming the abrasive gripping surfacesof the clamp. The threaded opening centrally'of jaw plate 28 mates withthe threads on sleeve 25, whereas outer plate 29 has a slightly largersmooth opening 30 slidable freely along sleeve 25. Astiff compressionspring 31 encircles sleeve 25 with one end bearing against plate 29 andthe other end bearing against a washer 32 at the forward end of handgrip 20.

Suitable means are provided for preventing the clamping plates 28 and 29from rotating as sleeve 25 is turned, as, for example, a pair of guidepins extending loosely through aligned openings 34 in plates 28` and 29,these pins being anchored in'recesses 35 in the main body of While apair of guide pins 33 are here shown and are preferred, it will beappreciated that a single pin may be used.

Strips of abrasive material 37 and 38 are' shown as mounted along theopposite sides of main body 11. Such strips may-have either a paper or afabric backing and a face covering of abrasive powder or grit securedthereto by a. suitable bonding agent. These strips have a width grindingwith the second strip merely -by reversing "the position of the `tilewith respect to the surface being iinished.

The manner in which the abrasive strips are mounted will be quiteapparent from the foregoing description lof the file construction. lTwostrips 37 and 38 of abrasive materialare cut to suitable equal lengthsand the opposite ends are foldediover or sharply creased transversely ofthe strips as along transverse lines 39 and 40, these two crease linesbeing equally spaced apart Vlongitudinally of the strips. Hand grip 2i)'is rotated -in a direction to thread plate 28 toward the `rear end ofthe main body thereby relaxing the compressive Vforces acting Von spring3l. In this position, the Vrear ends of the strips may be readilywithdrawn from the clamping plates.

The forward ends .of the strips are released by grasping the end yofkeeper dowel 17 .between the thumb and fore-linger and pulling itbackwardly compressing elastic strip 16 thereby releasing the forwardends of the abrasive strips from groove i3. Dowel pin .17 is lsimilarlyheld retracted while the creased tabs of a pair of lnew abrasive stripsare inserted against the side walls '14 of clamping groove i3. Whenproperly positioned against walls 14, the dowel is released allowingrubber strip 16 to press the dowel toward the mouth of the groovethereby wedging the Strips firmly lagainst the groove `side walls.

The turned over rear ends of Ystrips '37, 38 arev the'n itted betweenclamping plates ,23 and 29 and held `in PlaC therein by :light fingerpressure as Vhand grip '2li lis rotated wto thread plate ,28 alongsleeve 2 6 toward the hand grip as spring .3l is compressed toforceplate 29 into firm gripping `contact with the strip ends. Furtherrotation of the hand .grip increases both the clamping pressure on thestrip ends as well as the tension on the strips, the rotation of thegrip being discontinued when the strips are ata desired'tautness. The leis now ready for use and may be ,employed in the usual .manner to abradeand then polish surfaces of metal, wood, plastic o r the like.

While the particular hand polishing file herein shown and disclosed indetail,y is ful-ly capable of attaining the objects and ,providing theadvantages `hereinbefore stated, it is to be understood that Vit ismerely -illustrative of the presently preferred embodiments of theinvention and that no limitations kare .intended tor-ther details ofconstruction vor design herein vshown other than yas defmedin theappended claims.

I claim:

`1. A hand file adapted Vfor .use with replaceable strips of abrasivematerial, said 'tile comprising a'rigd backing member having a hand griprigidly` and adjustably secured to one end thereof, means at 'the'opposite'fends of said rigid member for releasably kclamping the`opposite ends of a strip of abrasive material therein, and-meansoperable by rotation of, said hand grip independently of ysaid clampingmeans for adjusting :the tension on said strip Vof abrasive materiallongitudinally thereof. t

2. A hand iile as defined 'in .claim `l including a plurality of stripsof abrasive material releasably 'supported along the opposite flatsurfaces of said rigid imemberfea'ch adapted to be itensionedsimultaneously by Vthe adjustment of said hand grip.

3. A handfiile as ydefined in claim l wherein the means for holding saidabrasive. strip ,to the forwardend of said rigid member comprises agroove acrossthetend `of said member, and self-clampingresilientlybacked means seated in `said groove operable to clampthe end yof anabrasive strip releasably in place in said groove.

4. A hand file adapted to support a pair of abrasive strips stretchedtaut flat against an elongated rigid backing member, said backing memberhaving wide dat surfaces on the opposite sides thereof, a groove acrossone end of said backing member having side walls converging toward theentrance end thereof, a clamping member loosely supported lengthwise ofsaid groove and having a width greater than the mouth of said groove,resilient means urging said clamping member toward the mouth of thegroove and being effective in cooperation with said clamping member toclampv the ends of abrasive strips against the side walls of saidgroove, and means at the opposite end of said backing member forclamping and tensioning the opposite ends of strips of abrasive materialextending along the at sides of the backing member.

5. A hand iile as defined in claim 4 wherein said means for tensioningstrips of abrasive material'includes a hand grip rotatably secured tothe end Vof said backing member, and means controlled by the rotation ofsaid hand grip in one direction to tension strips of abrasive anchoredto the groovedtend of said backing member and operable to slacken saidabrasive strips when vrotated in the opposite direction.

6. A `hand file for use with replaceable strips of liexible abrasivematerial, said file comprising a long iiat back-ing member having anarrow mouthed groove across one end, said groove being adapted to seatthe ends of abrasive material, `resilient self-locking means manuallydepressible to receive the ends of abrasive strips and for automaticallyclamping the same in place in said groove, a hand grip rotatablysupported at the other end of said backing member, resilient clampingmeans operatively associated with said hand grip for clamping 'theadjacent ends of abrasive strips, said hand grip be'ing 'rotatable toeffect displacement of said/clamping means relative to said 'backingmember to tension said strips lengthwise off'said backing member whenrotated' in one direction andvto relax the tension on said str-ips whenrotated in Vthe everse direction.

7. A hand iile as dened in claim 6, said resilientclamping meansincluding a pair of clamping plates, threaded means rotatable with saidhand grip and passing freely through one plate into threaded engagementwith the other plate, and spring means interposed between said hand gripand said one plate for urging said plates together.

8. A hand lile as defined in claim 7 including guide pin means anchoredto the end portion of said backing member and extending through openingsin said plateslaterally offset from said threaded means and parallelthereto.

9. A hand tile for detachably clamping a liexible strip of abrasivematerial stretched taut along an elongated backing member, a handlemounted at one end of saidl member and rotatable about its longitudinalaxis, a threaded sleeve fixed to said handle and having its 'endr0-tatablygsupported adjacent the handle end of said backing member, a pairofclamping plates mounted on 'said sleeve one plate having threadedengagement with `said sleeve and the other being loosely journaledthereon, and spring means urging said loosely Jiournaled plateagainstthe other plate to grip tightlyvone end of an abrasive strip extendingalong said backing member. f

l0. A hand `file as defined in claim 9 includiugjstationary guide meansiixed to said backing member and extending through guide passage meanson said plates tohld the same against rotation with said sleeve'an'dsaid'handle as the latter are rotated to tension and slacken an abrasivestrip, said guide means having one end anchored "to said backing member.

11. A hand tile for detachably supporting a flexible strip of abrasivematerial stretched taut along the iiat surface of a backing member, saidbacking memberhaving clamping and adjustable tensioning means at oneAend thereof adapted yto -grip vfirmly one end of an vabrasive asamsostrip, and means for releasably anchoring the strip to the opposite endof the backing member, said anchoring means including a groove acrossthe end of backing member, the side walls of said groove converging to anarrow mouth, a keeper extending along said groove and freelf.y movabletherein but having a Width greater than the mouth portion of saidgroove, and resilient means urging said keeper toward said groove mouthand eective in cooperation with said keeper to wedge the end of anabrasive strip between said keeper and one Wall of said groove.

l2. A hand lfile as dened in claim l1 wherein said backing member has apair of flat surfaces along the opposite sides thereof and parallel tothe longer axis of said References Cited in the le of this patent yUNITED STATES PATENTS 1,274,928 Mauer Auge, 191s FOREIGN PATENTS 201,977Great Britain Aug. 13, 1923

